Boston Marathon Bombings

New Traffic Data Show Impact of Bomber Manhunt

So many Bostonians stayed home during the manhunt for a suspect in the marathon bombings on April 19 that there was a dramatic effect on average traffic congestion across a wide swath of Massachusetts and southern New Hampshire, according to data released Friday.

Average traffic congestion dipped as much as two-thirds below the week-earlier level in a region that extends north of Nashua, N.H., west of Worcester, Mass., and south to the Connecticut and Rhode Island borders, according to Inrix, a Kirkland (Wash.) company that supplies congestion data to navigation systems for fleets and private vehicles. The company furnished its data for metro Boston at the request of Bloomberg Businessweek.

The big decline was in Boston itself and its inner suburbs after Massachusetts Governor Deval Patrick urged people to “shelter in place” as police searched for Dzhokhar Tsarnaev, the second suspect in the marathon bombings. The Boston Globereported that “Boston’s streets resembled deserted canyons.” Photographs taken that day back up that account.

Traffic in outlying areas was presumably closer to normal, but metro Boston is so big that the drop in its congestion weighed heavily on the entire region’s average. At its lightest, traffic in the metro area on April 19 was about as light as on the morning of the marathon on April 15, when Massachusetts celebrated Patriot’s Day with a day off from work and a good number of people were watching the Boston Marathon in person or on television.